I'm miserable

I'm miserable I have been stammering for years now, but it's been really affecting me this year. I've been losing relationships at work and school because i can't say anything without struggling for ages. It's been ruining my life and my self esteem. I've tried online courses to try and fix my stammering but nothing works. If anyone else has experienced this, please could you give me some advice on how to stop stammering or what you did to stop.